It has been discussed and put to rest for ages. Your verses aren't related to salvation of the unborn or childrent but here are three sources showing that age is irrelevant.

12 For the generations to come every male among you who is eight days old must be circumcised, including those born in your household or bought with money from a foreigner—those who are not your offspring. 13 Whether born in your household or bought with your money, they must be circumcised. My covenant in your flesh is to be an everlasting covenant. 14 Any uncircumcised male, who has not been circumcised in the flesh, will be cut off from his people; he has broken my covenant.” (Genesis 17:12-14)

Of course now we have a new Covenant and baptism has accompanied the new Covenant in the same manner as circumcision in the old Covenant.

[5] Jesus answered: Amen, amen I say to thee, unless a man be born again of water and the Holy Ghost, he cannot enter into the kingdom of God. (John 3:5)

Council of Trent, Catechism of Trent

Besides, it is not to be supposed that Christ the Lord would have withheld the Sacrament and grace of Baptism from children, of whom He said: Suffer the little children, and forbid them not to come to me; for the kingdom of heaven is for such; ° whom also He embraced, upon whom He imposed hands, to whom He gave His blessing.

Moreover, when we read that an entire family was baptised by Paul, it is sufficiently obvious that the children of the family must also have been cleansed in the saving font.

Circumcision, too, which was a figure of Baptism, affords strong argument in proof of this practice. That children were circumcised on the eighth day is universally known. If then circumcision, made by hand, in despoiling of the body of the flesh, was profitable to children, it is clear that Baptism, which is the circumcision of Christ, not made by hand, is also profitable to them.